[nvim] Initial nvim-cmp configuration.

.config/nvim/init.vim

@@ -4,6 +4,40 @@ source ~/.vimrc
 
 lua << EOF
 
+-- Setup nvim-cmp.
+vim.opt.completeopt = {"menu", "menuone", "noselect"}
+
+local cmp = require'cmp'
+
+cmp.setup({
+    snippet = {
+        expand = function(args)
+            require('luasnip').lsp_expand(args.body) -- For `luasnip` users.
+        end,
+    },
+    mapping = {
+        -- ['<C-b>'] = cmp.mapping(cmp.mapping.scroll_docs(-4), { 'i', 'c' }),
+        -- ['<C-f>'] = cmp.mapping(cmp.mapping.scroll_docs(4), { 'i', 'c' }),
+        ['<C-Space>'] = cmp.mapping(cmp.mapping.complete(), { 'i', 'c' }),
+        -- ['<C-y>'] = cmp.config.enable, -- Specify `cmp.config.disable` if you want to remove the default `<C-y>` mapping.
+        -- ['<C-e>'] = cmp.mapping({
+        --     i = cmp.mapping.abort(),
+        --   c = cmp.mapping.close(),
+        -- }),
+        ['<CR>'] = cmp.mapping.confirm({ select = true }), -- Accept currently selected item. Set `select` to `false` to only confirm explicitly selected items.
+    },
+    sources = cmp.config.sources({
+        { name = 'nvim_lsp' },
+        { name = 'luasnip' }, -- For luasnip users.
+    },
+    {
+        { name = 'buffer' },
+    })
+})
+
+-- Setup lspconfig: capabilities is passed to lspconfig.$server.setup
+local capabilities = require('cmp_nvim_lsp').update_capabilities(vim.lsp.protocol.make_client_capabilities())
+
 -- Set LSP keymappings in on_attach (i.e. only in buffers with LSP active)
 local on_attach = function(client, bufnr)
     opts = { noremap=true, silent=true }
@@ -25,6 +59,7 @@ require'lspconfig'.julials.setup({
                util.path.dirname(fname)
     end,
     on_attach = on_attach,
+    capabilities = capabilities,
 })
 
 EOF

.vimrc

@@ -21,7 +21,17 @@ call plug#begin('~/.vim/plugged')
     Plug 'tpope/vim-fugitive'
 
     if has('nvim')
+        " LSP helpers
         Plug 'neovim/nvim-lspconfig'
+        " nvim-cmp and completion sources
+        Plug 'hrsh7th/cmp-nvim-lsp'
+        Plug 'hrsh7th/cmp-buffer'
+        Plug 'hrsh7th/cmp-path'
+        " Plug 'hrsh7th/cmp-cmdline'
+        Plug 'hrsh7th/nvim-cmp'
+        " Snippet engine required for nvim-cmp (expands things from LS)
+        Plug 'L3MON4D3/LuaSnip'
+        Plug 'saadparwaiz1/cmp_luasnip'
     end
 
 call plug#end()